Today, several types of wearable device exist, with development of various types of wearable technologies and advancements in wearable computing. The term ‘wearable device’ refers to any electronic device or product which can be worn by a subject, e.g. a person, to integrate computing in his daily activity or work and use technology to avail advanced features & characteristics.
Typically, any wearable device may include one or more of the following elements including sensors, actuators, image and/or speech recognition technologies, positioning and/or networking chips, displays and/or optoelectronics and specialty monitoring devices. The emphasis on using wearable devices for fitness, health monitoring, entertainment, enterprise and industrial applications has been increasing with advancements such as stretchable electronics, flexible circuits, conducting fabrics, long lasting batteries and smaller specialty wearable sensors.
Remote monitoring and wearable technologies could also help to effectively manage health, monitor safety and reduce the staggering health care costs. For instance, health patches including means for measuring vital signs or any signals from the subject are currently in development for use in the hospital and at home.
As long lasting patches are very important, battery management becomes more and more relevant. To power up patches, switches can be used to activate the patch just before operation. This will safe battery power and increase life time. Besides the life time, costs will also play an important role, since the patches are (semi-)disposable. Additionally, switches will involve extra costs which is not desired in disposables.
Once solution to the problem of how to switch on the patch is the use of a zinc-air battery. The patch is enclosed in a sealed package and so the battery is deactivated. Once the package is opened by the user a chemical process inside the battery will start immediately and power is available. This results in powering up the system and the patch is ready to work. However, problems with bad sealed packages have been experienced. Due to pre-discharge of the battery the patch will not work once the user (e.g. a caregiver or nurse) wants to place the patch onto the patient. Another issue is the patch-patient pairing. For this purpose a Bluetooth smart radio may be placed on board of the patch, and with an application program e.g. on a tablet or smartphone pairing has to be done. Having multiple unassigned Bluetooth devices on air can, however, result in wrong patch-patient paring which will have serious consequences.
US2004/0131897 discloses an active wireless tagging system for a flexible peel-and-stick battery-operated device. The device comprises an RFID tag for communication with a remote RF interrogator. An RF-activated switch serves to connect the thin-film battery to the electronic circuit of the tag. RF energy received by the antenna is detected and amplified. A switch is closed operatively coupling battery power to the electronics circuit.